This invention relates to improvements in apparatuses for charging or filling containers with fluid substances (hereinafter referred to as filling apparatuses) and more particularly to a filling quantity regulating system capable of automatically adjusting filling quantities in a filling apparatus.
In the prior art there have been filling apparatuses of the type in which a fluid substance to be charged into containers is introduced into a plurality of charging cylinders and is then pushed out by respective pistons in metered quantity into corresponding containers.
In an apparatus of this class, when deviations in the filling quantity occur from cylinder to cylinder, or when fluctuations in the filling quantity of all cylinders occur, it has heretofore been the practice to adjust the filling quantity by manually varying the limit position of retraction or intake stroke of each piston, thereby to adjust the volume within the cylinder for introduction of the material to be charged. In the case of a so-called rotary type filling apparatus in which charging cylinders are disposed in a ring around a main spindle or shaft to revolve thereabout, the above mentioned adjustment during operation is accompanied by danger and is practically impossible since all cylinders are undergoing revolution around the main shaft. Consequently, there is the inconvenient necessity of stopping the operation of the apparatus each time an adjustment is to be made.
The above mentioned fluctuation in the filling quantity occurs as a result of causes such as subtle variations in the states of seals of the pistons and fluctuations in sepcific gravity due to subtle variations in conditions, such as the blending of the material being charged and the environmental temperature. As a consequence, the above mentioned adjustment of filling quantity must be carried out relatively frequently. This gives rise to an undesirable drop in operational efficiency due to frequent stoppages of the apparatus. Of course, a filling quantity regulating system adapted for the container filling apparatus as mentioned above and comprising a specific limit adjusting mechanism, for example, such system as disclosed in U.S. Pat. No. 3,835,898 has been proposed for eliminating the disadvantages mentioned above. However, a conventional system is relatively complex and expensive.